このJDO例外のデバッグを開始するにはどうすればよいですか？

Question

Eclipseでホストされたモードでアプリケーションを実行しているときに、この例外が発生することがあります。奇妙なことに、それは一貫して起こらないということです。アプリケーションを再コンパイルして再起動すると、時々発生します。 Eclipseを再起動するとコードが変更されることはありません。誰がここで何が起こっているかもしれないかについての考えを持っていますか？それとも、どこから見始めるだろう？

 
[ERROR] javax.servlet.ServletContext log: Exception while dispatching incoming RPC call 
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract com.grgcomponents.coatl.client.auth.TwitterUser com.grgcomponents.coatl.client.auth.TwitterLoginService.getLoggedInUser(java.lang.String) throws java.lang.IllegalArgumentException' threw an unexpected exception: java.lang.UnsupportedOperationException 
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:378) 
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:581) 
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:207) 
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:243) 
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) 
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:58) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) 
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) 
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) 
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) 
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) 
    at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at org.mortbay.jetty.Server.handle(Server.java:326) 
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) 
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) 
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) 
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) 
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) 
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) 
    at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582) 
Caused by: java.lang.UnsupportedOperationException 
    at org.datanucleus.store.appengine.EntityUtils.getPropertyName(EntityUtils.java:62) 
    at org.datanucleus.store.appengine.DatastoreFieldManager.getPropertyName(DatastoreFieldManager.java:1073) 
    at org.datanucleus.store.appengine.DatastoreFieldManager.fetchObjectField(DatastoreFieldManager.java:309) 
    at org.datanucleus.store.appengine.DatastoreFieldManager.fetchLongField(DatastoreFieldManager.java:429) 
    at org.datanucleus.state.AbstractStateManager.replacingLongField(AbstractStateManager.java:1148) 
    at com.grgcomponents.coatl.server.persisted.TwitterOAuthTokens.jdoReplaceField(TwitterOAuthTokens.java) 
    at com.grgcomponents.coatl.server.persisted.TwitterOAuthTokens.jdoReplaceFields(TwitterOAuthTokens.java) 
    at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2772) 
    at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2791) 
    at org.datanucleus.store.appengine.DatastorePersistenceHandler.fetchObject(DatastorePersistenceHandler.java:480) 
    at org.datanucleus.state.JDOStateManagerImpl.validate(JDOStateManagerImpl.java:4263) 
    at org.datanucleus.ObjectManagerImpl.findObject(ObjectManagerImpl.java:2444) 
    at org.datanucleus.jpa.EntityManagerImpl.find(EntityManagerImpl.java:234) 
    at org.datanucleus.store.appengine.jpa.DatastoreEntityManager.find(DatastoreEntityManager.java:56) 
    at com.grgcomponents.coatl.server.auth.TwitterLoginServiceImpl.getCurrentUser(TwitterLoginServiceImpl.java:45) 
    at com.grgcomponents.coatl.server.auth.TwitterLoginServiceImpl.getLoggedInUser(TwitterLoginServiceImpl.java:30) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) 
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562) 
    ... 30 more 


[ERROR] javax.servlet.ServletContext log: Exception while dispatching incoming RPC call 
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String com.grgcomponents.coatl.client.preferences.UserSettingsService.getSetting(java.lang.String,java.lang.String)' threw an unexpected exception: java.lang.UnsupportedOperationException 
    at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:378) 
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:581) 
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:207) 
    at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:243) 
    at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:637) 
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717) 
    at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1166) 
    at com.google.appengine.api.blobstore.dev.ServeBlobFilter.doFilter(ServeBlobFilter.java:58) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at com.google.appengine.tools.development.StaticFileFilter.doFilter(StaticFileFilter.java:122) 
    at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1157) 
    at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:388) 
    at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216) 
    at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182) 
    at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765) 
    at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:418) 
    at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:70) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:349) 
    at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) 
    at org.mortbay.jetty.Server.handle(Server.java:326) 
    at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542) 
    at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:938) 
    at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:755) 
    at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218) 
    at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404) 
    at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) 
    at org.mortbay.thread.QueuedThreacom.google.gwt.user.client.rpc.StatusCodeException: 500 The call failed on the server; see server log for details 
    at com.google.gwt.user.client.rpc.impl.RequestCallbackAdapter.onResponseReceived(RequestCallbackAdapter.java:192) 
    at com.google.gwt.http.client.Request.fireOnResponseReceived(Request.java:287) 
    at com.google.gwt.http.client.RequestBuilder$1.onReadyStateChange(RequestBuilder.java:395) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) 
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) 
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157) 
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessagesWhileWaitingForReturn(BrowserChannelServer.java:326) 
    at com.google.gwt.dev.shell.BrowserChannelServer.invokeJavascript(BrowserChannelServer.java:207) 
    at com.google.gwt.dev.shell.ModuleSpaceOOPHM.doInvoke(ModuleSpaceOOPHM.java:126) 
    at com.google.gwt.dev.shell.ModuleSpace.invokeNative(ModuleSpace.java:561) 
    at com.google.gwt.dev.shell.ModuleSpace.invokeNativeObject(ModuleSpace.java:269) 
    at com.google.gwt.dev.shell.JavaScriptHost.invokeNativeObject(JavaScriptHost.java:91) 
    at com.google.gwt.core.client.impl.Impl.apply(Impl.java) 
    at com.google.gwt.core.client.impl.Impl.entry0(Impl.java:214) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at com.google.gwt.dev.shell.MethodAdaptor.invoke(MethodAdaptor.java:103) 
    at com.google.gwt.dev.shell.MethodDispatch.invoke(MethodDispatch.java:71) 
    at com.google.gwt.dev.shell.OophmSessionHandler.invoke(OophmSessionHandler.java:157) 
    at com.google.gwt.dev.shell.BrowserChannelServer.reactToMessages(BrowserChannelServer.java:281) 
    at com.google.gwt.dev.shell.BrowserChannelServer.processConnection(BrowserChannelServer.java:531) 
    at com.google.gwt.dev.shell.BrowserChannelServer.run(BrowserChannelServer.java:352) 
    at java.lang.Thread.run(Thread.java:680) 
dPool$PoolThread.run(QueuedThreadPool.java:582) 
Caused by: java.lang.UnsupportedOperationException 
    at org.datanucleus.store.appengine.EntityUtils.getPropertyName(EntityUtils.java:62) 
    at org.datanucleus.store.appengine.DatastoreFieldManager.getPropertyName(DatastoreFieldManager.java:1073) 
    at org.datanucleus.store.appengine.DatastoreFieldManager.fetchObjectField(DatastoreFieldManager.java:309) 
    at org.datanucleus.store.appengine.DatastoreFieldManager.fetchLongField(DatastoreFieldManager.java:429) 
    at org.datanucleus.state.AbstractStateManager.replacingLongField(AbstractStateManager.java:1148) 
    at com.grgcomponents.coatl.server.persisted.TwitterOAuthTokens.jdoReplaceField(TwitterOAuthTokens.java) 
    at com.grgcomponents.coatl.server.persisted.TwitterOAuthTokens.jdoReplaceFields(TwitterOAuthTokens.java) 
    at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2772) 
    at org.datanucleus.state.JDOStateManagerImpl.replaceFields(JDOStateManagerImpl.java:2791) 
    at org.datanucleus.store.appengine.DatastorePersistenceHandler.fetchObject(DatastorePersistenceHandler.java:480) 
    at org.datanucleus.state.JDOStateManagerImpl.validate(JDOStateManagerImpl.java:4263) 
    at org.datanucleus.ObjectManagerImpl.findObject(ObjectManagerImpl.java:2444) 
    at org.datanucleus.jpa.EntityManagerImpl.find(EntityManagerImpl.java:234) 
    at org.datanucleus.store.appengine.jpa.DatastoreEntityManager.find(DatastoreEntityManager.java:56) 
    at com.grgcomponents.coatl.server.UserUtil.getTwitter(UserUtil.java:40) 
    at com.grgcomponents.coatl.server.UserUtil.getUserSetting(UserUtil.java:62) 
    at com.grgcomponents.coatl.server.preferences.UserSettingsServiceImpl.getSetting(UserSettingsServiceImpl.java:14) 
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) 
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) 
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) 
    at java.lang.reflect.Method.invoke(Method.java:597) 
    at com.google.appengine.tools.development.agent.runtime.Runtime.invoke(Runtime.java:100) 
    at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:562) 
    ... 30 more 

ここで私が持続しようとしているクラスです：

package com.grgcomponents.coatl.server.persisted; 

import javax.persistence.Entity; 
import javax.persistence.Id; 

@Entity 
public class TwitterOAuthTokens { 
@Id 
private String loginManagerCookie; 

private String requestTokenKey; 

private String requestTokenSecret; 

private String userToken; 

private String userTokenSecret; 

private long lastUsed; 

public String getLoginManagerCookie() { 
    return loginManagerCookie; 
} 

public void setLoginManagerCookie(String loginManagerCookie) { 
    this.loginManagerCookie = loginManagerCookie; 
} 

public String getUserToken() { 
    return userToken; 
} 

public void setUserToken(String userToken) { 
    this.userToken = userToken; 
} 

public String getUserTokenSecret() { 
    return userTokenSecret; 
} 

public void setUserTokenSecret(String userTokenSecret) { 
    this.userTokenSecret = userTokenSecret; 
} 

public String getRequestTokenKey() { 
    return requestTokenKey; 
} 

public void setRequestTokenKey(String requestTokenKey) { 
    this.requestTokenKey = requestTokenKey; 
} 

public String getRequestTokenSecret() { 
    return requestTokenSecret; 
} 

public void setRequestTokenSecret(String requestTokenSecret) { 
    this.requestTokenSecret = requestTokenSecret; 
} 

public long getLastUsed() { 
    return lastUsed; 
} 

public void setLastUsed(long lastUsed) { 
    this.lastUsed = lastUsed; 
} 

} 

ここでは、実際に（私たちはgetTwitter（文字列で入力してください）失敗しているように見える、そして障害が最後に発生したコールですライン：

public static Twitter getTwitter(String loginManagerId) 
{ 
    if(loginManagerId == null) 
     return null; 

    EntityManager em = CoatlEntityManagerFactory.getDefault() 
      .createEntityManager(); 

    return getTwitter(loginManagerId, em); 
} 

public static Twitter getTwitter(String loginManagerId, EntityManager em) 
{ 
    if(loginManagerId == null) 
     return null; 

    TwitterOAuthTokens storedTokens = em.find(TwitterOAuthTokens.class, 
      loginManagerId); 

Answer 1

これは、任意の永続クラスに随時起こり散発的なエラーですが、moreso並列に多く使用されているものにそれはJDOとJPAで発生し、それがあるかのように思えます。ローカルデータストアは特定のテーブル/エンティティグループをロックし、それを解放することを忘れてしまいます。これ以降のds操作の呼び出しはすべて失敗します。私は通常、Eclipseを再起動する必要はありません。サーバーを停止するだけで問題が解決する傾向があります。そうでない場合は、完全リフレッシュ/クリーンビルドがトリックを行います。

唯一の実際の解決策は、理論的には一度に1つのスレッドのみがあなたのエンティティにアクセスしていることを保証する同期コードブロックの内部にget（）またはput（）呼び出しを入れているようです。 http://code.google.com/p/datanucleus-appengine/issues/detail?id=203